/* Copyright 2023 Dual Tachyon
 * https://github.com/DualTachyon
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *     Unless required by applicable law or agreed to in writing, software
 *     distributed under the License is distributed on an "AS IS" BASIS,
 *     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *     See the License for the specific language governing permissions and
 *     limitations under the License.
 */


#include "i2c.h"
#include "port.h"
#include "delay.h"
#define   SYSTICK_DelayUs delay_us
void I2C_Start(void) {
    GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
    SYSTICK_DelayUs(1);
    GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);
    GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
    SYSTICK_DelayUs(1);
    GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);
}

void I2C_Stop(void) {
    GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
    SYSTICK_DelayUs(1);
    GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);
    GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);
    GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
    SYSTICK_DelayUs(1);
}

uint8_t I2C_Read(bool bFinal) {
    uint8_t i, Data;

    PORTCON_PORTA_IE |= PORTCON_PORTA_IE_A11_BITS_ENABLE;
    PORTCON_PORTA_OD &= ~PORTCON_PORTA_OD_A11_MASK;
    GPIOA->DIR &= ~GPIO_DIR_11_MASK;

    Data = 0;
    for (i = 0; i < 8; i++) {
        GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
        SYSTICK_DelayUs(1);
        GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
        SYSTICK_DelayUs(1);
        Data <<= 1;
        SYSTICK_DelayUs(1);
        if (GPIO_CheckBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA)) {
            Data |= 1U;
        }
        GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
        SYSTICK_DelayUs(1);
    }

    PORTCON_PORTA_IE &= ~PORTCON_PORTA_IE_A11_MASK;
    PORTCON_PORTA_OD |= PORTCON_PORTA_OD_A11_BITS_ENABLE;
    GPIOA->DIR |= GPIO_DIR_11_BITS_OUTPUT;
    GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);
    if (bFinal) {
        GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
    } else {
        GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
    }
    SYSTICK_DelayUs(1);
    GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);
    GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);

    return Data;
}

int I2C_Write(uint8_t Data) {
    uint8_t i;
    int ret = -1;

    GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);
    for (i = 0; i < 8; i++) {
        if ((Data & 0x80) == 0) {
            GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
        } else {
            GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
        }
        Data <<= 1;
        SYSTICK_DelayUs(1);
        GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
        SYSTICK_DelayUs(1);
        GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
        SYSTICK_DelayUs(1);
    }

    PORTCON_PORTA_IE |= PORTCON_PORTA_IE_A11_BITS_ENABLE;
    PORTCON_PORTA_OD &= ~PORTCON_PORTA_OD_A11_MASK;
    GPIOA->DIR &= ~GPIO_DIR_11_MASK;
    GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);
    SYSTICK_DelayUs(1);
    GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);

    for (i = 0; i < 255; i++) {
        if (GPIO_CheckBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA) == 0) {
            ret = 0;
            break;
        }
    }

    GPIO_ClearBit(&GPIOA->DATA, GPIOA_PIN_I2C_SCL);
    SYSTICK_DelayUs(1);
    PORTCON_PORTA_IE &= ~PORTCON_PORTA_IE_A11_MASK;
    PORTCON_PORTA_OD |= PORTCON_PORTA_OD_A11_BITS_ENABLE;
    GPIOA->DIR |= GPIO_DIR_11_BITS_OUTPUT;
    GPIO_SetsBit(&GPIOA->DATA, GPIOA_PIN_I2C_SDA);

    return ret;
}

int I2C_ReadBuffer(void *pBuffer, uint16_t Size) {
    uint8_t *pData = (uint8_t *) pBuffer;
    uint16_t i;

    if (Size == 1) {
        *pData = I2C_Read(true);
        return 1;
    }

    for (i = 0; i < Size - 1; i++) {
        SYSTICK_DelayUs(1);
        pData[i] = I2C_Read(false);
    }

    SYSTICK_DelayUs(1);
    pData[i++] = I2C_Read(true);

    return Size;
}

int I2C_WriteBuffer(const void *pBuffer, uint8_t Size) {
    const uint8_t *pData = (const uint8_t *) pBuffer;
    uint8_t i;

    for (i = 0; i < Size; i++) {
        if (I2C_Write(*pData++) < 0) {
            return -1;
        }
    }

    return 0;
}

